Single, dual, and multiple pole piece ferrofluid seal-type apparatus are known and are designed to provide a ferrofluid seal about a moving element, such as a rotatable shaft element, either as an exclusion-type single or dual pole piece seal or as a pressure-type multiple-stage seal.
In single pole piece-permanent magnet ferrofluid seal apparatus of the type disclosed in U.S. Ser. No. 450,339, as well as in other seal apparatus, the washer-like pole piece element is secured to the annular permanent magnet by staking the elements together or more commonly by bonding the flat opposing surface of the pole piece element and the permanent magnet together employing a high strength adhesive material.
It is however desireable to provide a simple, rapid, low cost and yet effective method for the manufacture of a single or dual pole piece-permanent magnet apparatus and to provide an improved single and dual pole piece ferrofluid seal apparatus, which method and apparatus overcome certain disadvantages of prior art methods and apparatus and provide new and improved advantages.